Communication apparatus and method of controlling communication thereof

ABSTRACT

Disclosed is a communication apparatus in a network system constituted by a plurality of communication apparatuses, wherein the fact that a specific communication apparatus connected to a temporary network constructed temporarily has left the temporary network is detected. In response to the specific communication apparatus leaving the temporary network, another communication apparatus connected to the temporary network is allowed to return to the original network.

This application is a divisional of application Ser. No. 12/811,395filed on Jul. 1, 2010, which was the National Stage of InternationalApplication No. PCT/JP2009/054599 filed on Mar. 4, 2009.

TECHNICAL FIELD

The present invention relates to a communication apparatus in a networksystem constituted by a plurality of communication apparatuses, and to amethod of controlling communication in this apparatus.

BACKGROUND ART

Wireless LAN products available on the market includedual-mode-compatible products having both an access point (AP) functionand a station (STA) function.

Further, functions for the purpose of enhancing security and forutilizing wireless bandwidth effectively have also been provided. Forexample, the specification of Japanese Patent Laid-Open No. 2006-101416provides a communication scheme for connecting to a first network,sending and receiving information relating to the construction of a newsecond network within the first network and shifting to the secondnetwork in order to execute an application.

However, with this example of the prior art, a problem which arises isthat if a station participating in the second network leaves thenetwork, other stations in the second network cannot return to the firstnetwork.

FIG. 22 is a sequence diagram useful in describing this problem thatarises in the conventional network communication control method. In thisexample, a personal computer (PC) 101, display 102, printer 103 anddigital video camera 104 are connected to an access point (AP) 100 andform a home network. Under these conditions, the digital video camera104 requests the formation of a temporary network and the display 102forms the temporary network by acting as an AP. Thereafter, the digitalvideo camera 104 leaves the temporary network.

First, the digital video camera 104 sends the printer 103 a networktransition request via the AP 100 (S2200). In response to this networktransition request, the printer 103 issues a network transition response(S2201). Similarly, the digital video camera 104 sends the display 102 anetwork transition request via the AP 100 (S2202), and the display 102issues a network transition response (S2203).

Next, the display 102 ceases operating in the STA mode (S2204) andoperates in the AP mode (S2205). The display 102 then transmits a beaconsignal (not shown) periodically. When the display 102 operates in the APmode, the camera 104 and printer 103 each execute processing to connectto the display 102 (S2206 to S2209) and form a temporary network. Byvirtue of the temporary network, the camera 104 displays a streamingimage on the display 102 and prints to the printer 103.

Subsequently, if the user of the camera 104 cuts off power to the cameraor if communication quality deteriorates, communication between thecamera 104 and display 102 is interrupted (S2210). Since the display 102is operating as an AP in this case, it detects that the camera 104 hasleft the temporary network.

However, the connection between the display 102 and printer 103 ismaintained. As a result, the display 102 and printer 103 are left in astate in which they are not being used by anyone and cannot return tothe home network.

Accordingly, the personal computer 101 cannot access the display 102 andprinter 103 via the AP 100 of the home network (S2211, S2212, S2213).

Thus, as described above, a problem with the conventional communicationcontrol method is that the system is not user friendly as far as devicesconnected to the home network are concerned.

DISCLOSURE OF INVENTION

The present invention is such that in a situation where a specificcommunication apparatus has left a temporary network, all communicationapparatuses are allowed to return to the original network.

In accordance with an embodiment of the present invention, there isprovided a communication apparatus comprising: detecting means fordetecting that a specific communication apparatus connected to atemporary network that has been constructed temporarily has left thetemporary network; and returning means, responsive to the specificcommunication apparatus leaving the temporary network, for returninganother communication apparatus connected to the temporary network to anoriginal network to which it was connected prior to the connection tothe temporary network.

In accordance with an embodiment of the present invention, there isprovided a communication control method of a communication apparatus,comprising: a detecting step of detecting that a specific communicationapparatus connected to a temporary network that has been constructedtemporarily has left the temporary network; and responsive to thespecific communication apparatus leaving the temporary network, a returnstep of returning another communication apparatus connected to thetemporary network to an original network to which it was connected priorto the connection to the temporary network.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of the configuration of ahome network system according to a first embodiment of the presentinvention;

FIG. 2 is a diagram illustrating an example of the configuration of anetwork system newly constructed from the home network;

FIG. 3 is a diagram illustrating an example of the configuration of adisplay in the first embodiment;

FIG. 4 is a diagram illustrating in detail the structure of acommunication controller of the display in the first embodiment;

FIG. 5 is a sequence diagram illustrating communication control forallowing a communication apparatus to return from a temporary network toa home network in the first embodiment;

FIG. 6 is a flowchart illustrating communication control of acommunication apparatus in the first embodiment;

FIG. 7 is a sequence diagram illustrating operation in which a dualterminal returns from a temporary network to a home network in a firstmodification of the first embodiment;

FIG. 8 is a sequence diagram illustrating operation in which a dualterminal returns from a temporary network to a home network in a secondmodification of the first embodiment;

FIG. 9 is a diagram illustrating in detail the structure of thecommunication controller of the display in a second embodiment of thepresent invention;

FIG. 10 is a diagram illustrating in detail the content of a STAmanagement register;

FIG. 11 is a sequence diagram illustrating communication control forallowing each communication apparatus to return from a temporary networkto a home network in the second embodiment;

FIG. 12 is a flowchart illustrating communication control of acommunication apparatus in the second embodiment;

FIG. 13 is a diagram illustrating an example of communicationapparatuses connected to a temporary network in a third embodiment ofthe present invention;

FIG. 14 is a diagram illustrating an example of a STA managementregister of a display in the third embodiment;

FIG. 15 is a sequence diagram illustrating communication control forallowing each communication apparatus to return from a temporary networkto a home network in the third embodiment;

FIG. 16 is a flowchart illustrating communication control of acommunication apparatus in the third embodiment;

FIG. 17 is a sequence diagram illustrating communication control forallowing each communication apparatus to return from a temporary networkto a home network in a fourth embodiment of the present invention;

FIG. 18 is a flowchart illustrating communication control of acommunication apparatus in the fourth embodiment;

FIG. 19 is a diagram illustrating the content of the STA managementregister of a printer;

FIG. 20 is a diagram illustrating the content of the STA managementregister of a printer;

FIG. 21 is a diagram illustrating the content of the STA managementregister of a printer; and

FIG. 22 is a sequence diagram useful in describing a problem that ariseswith a network communication control method according to the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be described indetail with reference to the drawings.

[First Embodiment]

Described as a first embodiment is communication control in which, if aspecific communication apparatus that has shifted from a home network toa temporary network leaves the temporary network, another communicationapparatus in the temporary network is allowed to return to the homenetwork. First, the communication apparatus constituting the network andthe structure of the apparatus will be described with reference to FIGS.1 to 4.

FIG. 1 is a diagram illustrating an example of the configuration of ahome network system according to the first embodiment. Here personalcomputer (PC) 101, display 102, printer 103 and digital video camera 104are connected as stations (STA) to access point (AP) 100 and form a homenetwork 105. The display 102, printer 103 and camera 104 are dualterminals having both an AP function and a STA function and capable ofoperating in dual modes (the AP mode and STA mode).

Here an access point is an apparatus that accommodates a station andoperates as a base station. A station is an apparatus that participatesas a terminal in a network constructed by the access point andcommunicates wirelessly via the access point. Further, dual mode is amode in which operation is possible in both the AP mode, in which anapparatus operates as an access point, and in the STA mode, in which theapparatus operates as a station.

FIG. 2 is a diagram illustrating an example of the configuration of anetwork system constructed temporarily from the home network. In thisexample, the state shown is one in which the user of the camera 104requests the formation of a temporary network in order that the user mayuse the display 102 and printer 103, wherein the display 103 operates inthe AP mode to construct a temporary network 200. It should be notedthat the printer 103 and camera 104 also are capable of operating in theAP mode.

FIG. 3 is a diagram illustrating an example of the configuration of thedisplay 102 in the first embodiment. As illustrated in FIG. 3, thedisplay 102 includes an image processing unit 300, a display unit 301and a communication controller 302. Here the image processing unit 300executes processing of an image displayed on the display unit 301. Thecommunication controller 302 controls communication between thisapparatus and the other apparatuses shown in FIGS. 1 and 2.

FIG. 4 is a diagram illustrating in detail the structure of thecommunication controller 302 of the display 102 in the first embodiment.Although this embodiment is described taking the display 102 as anexample, it is assumed that the communication controllers of the otherdual terminals such as the printer 103 are similarly constructed.

A CPU 400 controls the overall communication controller 302 inaccordance with programs and data stored in a ROM 401. The ROM 401 has aSTA function control section 403 in which a program that causes thedisplay 102 to perform the STA function has been stored, and an APfunction control section 404 in which a program that causes the display102 to perform the AP function has been stored. Also provided within theROM 401 is a communication parameter storage unit 402 for storingcommunication parameters necessary in order to connect to the homenetwork 105 or temporary network 200.

A RAM 405 has an area (not shown) in which a program within the ROM 401is expanded, a mode management register 406 and an applicationmanagement register 407. The mode management register 406 stores whetherthe display 102 is operating in the AP mode or STA mode. Morespecifically, the CPU 400 writes logical “1” to the mode managementregister 406 if the display 102 operates in the AP mode and writeslogical “0” to the mode management register 406 if the display 102operates in the STA mode.

The application management register 407 manages the operating state of ahost application between this apparatus and another communicationapparatus such as the printer 103 or camera 104. If the host applicationis operating, the CPU 400 writes “1” to the application managementregister 407; otherwise, the CPU 400 writes “0” to the applicationmanagement register 407. It should be noted that the determination as towhether the application is operating can be made by determining whethera communication port has been opened for every communication apparatus.

The timer 408 is a programmable timer that is programmable by the CPU400. The timer measures a period of time that has been set by the CPU400 and causes the CPU 400 to generate an interrupt signal when the timeperiod elapses. A wireless unit 409 communicates wirelessly with othercommunication apparatuses via an antenna by a wireless LAN functioncompliant with IEEE 802.11.

Reference will now be had to FIGS. 5 and 6 to describe operation inwhich, after the camera 104 leaves the temporary network 200, theprinter 103 and display 102 return from the temporary network 200 to thehome network 105.

FIG. 5 is a sequence diagram illustrating communication control forallowing a communication apparatus to return from the temporary networkto the home network in the first embodiment.

FIG. 6 is a flowchart illustrating communication control of acommunication apparatus in the first embodiment. It should be noted thatthis communication control is executed by the communication controllersof the camera 104, display 102 and printer 103.

As illustrated in FIG. 5, the dual terminals of the camera 104, display102 and printer 103 form the temporary network 200 (600). At this timethe camera 104, display 102 and printer 103 each store communicationparameters, which are necessary for connection to the home network 105,in the respective communication parameter storage units 402. Further,since the display 102 is operating in the AP mode, “1” is written to itsmode management register 406, and since the camera 104 and printer 103are operating in the STA mode, “0” is written to their mode managementregisters 406.

The CPU 400 of the display 102 checks the mode management register 406and judges that the display 102 is operating in the AP mode (“YES” at601). Further, the CPUs 400 of the camera 104 and printer 103 checktheir mode management registers 406 and judge that these are operatingin the STA mode (“NO” at 601).

Here the user of the camera 104 operates the camera 104 andintentionally causes the camera 104 to leave the temporary network 200(S500). The CPU 400 of the display 102 then detects that the camera 104,which is the station under control, has left the temporary network 200(S501; “YES” at 602). The CPU 400 of the display 102 determines whetheror not the application involving the camera 104 is running based uponthe value in the application management register 407 (603).

If the value in the application management register 407 is “1”,indicating that the application is currently running (“YES” at 603),then the CPU 400 of the display 102 starts up the timer 408 (604) and areconnection request from the camera 104 is awaited. If the camera 104subsequently requests re-connection (“YES” at 605), control returns to602.

On the other hand, if the timer 408 times out (“YES” at 606) or it isdetermined that the application is not running (“NO” at 603), then alldual terminals (printer 103) are notified that the camera 104 has leftthe temporary network 200 (S502; 607). The CPU 400 of the display 102then halts operation in the AP mode (S503; 608) and shifts to the STAmode (S506; 609), after which this CPU 400 transmits a connectionrequest to the AP 100 (S507). When a connection response is receivedfrom the AP 100 (S508), the display 102 returns to the home network 105(610).

At this time the CPU 400 of the display 102 executes return using thecommunication parameters of the home network 105 stored in itscommunication parameter storage unit 402. Further, since the camera 400leaves the temporary network 200 at 611 owing to user operation (“YES”at 611), the CPU 400 of the camera 104 terminates processing.

On the other hand, the printer 103 does not leave the temporary network200 (“NO” at 611) and the CPU 400 of the printer 103 receivesnotification from the display 102 that the camera has left the temporarynetwork (S502; “YES” at 612). As a result, the CPU 400 of printer 103transmits a connection request to the AP 100 using the communicationparameters of the home network 105 stored in its communication parameterstorage unit 402 (S504). When a connection response is received from theAP 100 (S505), the printer returns to the home network 105 (610).

Thus, the communication apparatus 102 and display unit 103 can return tothe home network 105 and the personal computer 101 can use the display102 and printer 103.

In accordance with the first embodiment, unused devices are preventedfrom remaining in the temporary network 200 and a network that is easyfor the user of the home network 105 to use can be implemented.

It should be noted that although the display 102 notifies the printer103 in S502 and 607 that the camera has left the temporary network, thisnotification need not be given. Here, owing to termination of a beaconsignal (not shown) transmitted by the display 102, the printer 103 iscapable of detecting the termination of the AP function of the display102. The sequence in this case is illustrated in FIG. 7.

[First Modification]

FIG. 7 is a sequence diagram illustrating operation in which a dualterminal returns from a temporary network to a home network in a firstmodification of the first embodiment. Operations identical with those ofthe first embodiment shown in FIG. 5 are designated by like referencecharacters and need not be described again.

In a manner similar to that of the first embodiment, the CPU 400 of thedisplay 102 halts the AP function (S503) upon detecting (S501) that thecamera 104 has left the temporary network 200 in S500. Accordingly, theprinter 103 no longer receives (S701) the beacon received periodically(S700) from the display 102 and determines that the AP function of thedisplay 102 has halted (S702). By virtue of this determination, theprinter 103 returns to the home network 105 in a manner similar to thatof the first embodiment.

[Second Modification]

In another arrangement, rather than giving notification in S502 and 607that the temporary network has been left, it is permissible to use asignal (a “deauthentication” signal) that disconnects the printer 103from the temporary network 200.

After the disconnect signal is received, the printer 103 may try tore-connect to the temporary network 200 several times. By refusing allof these several re-connection attempts by the printer 103, the display102 can suggest to the printer 103 that it return to the home network105. The sequence in this case is illustrated in FIG. 8.

FIG. 8 is a sequence diagram illustrating operation in which a dualterminal returns from a temporary network to a home network in a secondmodification of the first embodiment. Operations identical with those ofthe first embodiment shown in FIG. 5 are designated by like referencecharacters and need not be described again.

If the CPU 400 of the printer 103 receives a disconnect signal from thedisplay 102 (S800), then it transmits a connection request to thedisplay 102 (S801). The CPU 400 of the display 102 responds to theconnection request with a connect response (=failure) (S801) and refusesre-connection of the printer 103. Further, similar processing isexecuted in S803 and S804.

Owing to refusal of connection requests several times in S801 to S804,the CPU 400 of the printer 103 decides return to the home network 105and returns to the home network 105 (S504, S505).

Further, it is obvious that similar effects can be obtained even if thenotification of leaving the temporary network in S502 in FIG. 5 isimplemented by a signal that instructs the printer 103 to return to thehome network 105.

Further, the dual terminal (camera 104) that will leave the temporarynetwork 200 may itself so notify the display 102 before leaving. In thisway it is possible for a dual terminal (the display 102) that detectssuch departure from the temporary network to make the detectionpromptly.

[Second Embodiment]

Next, a second embodiment of the present invention will be described indetail with reference to the drawings. According to the secondembodiment, a return to the home network is achieved when a specificcommunication apparatus having an application command function executedin a temporary network leaves the temporary network. Here the commandfunction is a function that designates printing in the case of aprinting application, or a function that selects an image and designatesdisplay of the image in the case of an application that selects anddisplays an image, etc.

A return to the home network is performed only in a case where thecommunication apparatus having this command function has left thetemporary network. As a result, as long as even one commanded terminalexists in the temporary network, the communication apparatus having thecommand function is capable of using the commanded terminal.

It should be noted that the communication apparatuses constituting thenetwork and the structure of the apparatus are the same as those of thefirst embodiment described above in conjunction with FIGS. 1 to 3.

FIG. 9 is a diagram illustrating in detail the structure of thecommunication controller 302 of the display 102 in the secondembodiment. As illustrated in FIG. 9, in the second embodiment, thearrangement of the first embodiment described above with reference toFIG. 4 is further equipped with a STA management register 900. FIG. 10is a diagram illustrating in detail the content of the STA managementregister 900.

As illustrated in FIG. 10, the STA management register 900 stores aserial number 1000, MAC address 1001, physical function 1002 and logicalfunction 1003 of each communication apparatuses that exists in thetemporary network 200. In a case where a communication apparatus thatexists in the temporary network 200 is the above-mentioned commandterminal, an entry to this effect is stored as the logical function 1003thereof.

Reference will now be had to FIGS. 11 and 12 to describe operation inwhich, after a command terminal has left the temporary network, a returnto the home network 105 is performed based upon information that hasbeen stored in the STA management register 900 of the display 102. Itshould be noted that operations similar to those of the first embodimentneed not be described again; only operations that differ will bedescribed.

FIG. 11 is a sequence diagram illustrating communication control forallowing each communication apparatus to return from the temporarynetwork to the home network in the second embodiment, and FIG. 12 is aflowchart illustrating communication control of a communicationapparatus in the second embodiment. It should be noted that thiscommunication control is executed by the communication controllers ofthe camera 104, display 102 and printer 103.

As illustrated in FIG. 11, after the camera 104, display 102 and printer103 construct the temporary network 200, the camera 104 places anindication of the fact that it itself is the command terminal in aterminal-function notification signal and sends this to the display 102(S1100). Further, the printer 103 places an indication of the fact thatit itself is not a command terminal in a terminal-function notificationsignal and sends this to the display 102 (S1101). On the other hand, thedisplay 102 receives the terminal function notifications from the camera104 and printer 103, whereupon the CPU 400 stores the MAC address 1001,physical function 1002 and logical function 1003 of each of thesedevices in the STA management register 900 (S1102).

The STA management register 900 of the display 102 at this time storesinformation in the manner shown in FIG. 10. Specifically, Serial No. 1is information relating to the camera 104, for which the MAC address1001 is “aa:aa:aa:aa:aa:aa”, the physical function 1002 is “STA” and thelogical function 1003 is “command terminal”. Further, Serial No. 2 isinformation relating to the printer 103, for which the MAC address 1001is “bb:bb:bb:bb:bb:bb”, the physical function 1002 is “STA” and thelogical function 1003 is “other”.

Assume that under these conditions, communication between the printer103 and display 102 is severed for some reason (S1103). When thisoccurs, the CPU 400 of the display 102 refers to the STA managementregister 900 and determines whether the printer 103 is the commandterminal (1200 in FIG. 12). Since printer 103 of Serial No. 2 underserial number 1000 is such that the logical function 1003 thereof is notthat of a command terminal in this example (“NO” at 1200), the CPU 400of the display 102 returns to the processing of 602.

Next, the camera 104 executes an application such as an image displaywith the display 102 (S1104) and the camera 104 leaves the temporarynetwork 200 in S500. When this occurs, the CPU 400 of the display 102refers to the STA management register 900 and determines whether thecamera 104 is the command terminal (1200). Since camera 104 of SerialNo. 1 under serial number 1000 is such that the logical function 1003thereof is that of a command terminal in this example (“YES” at 1200),the CPU 400 of the display 102 determines at 1201 whether a STA remainsin the temporary network 200. In this example, the printer 103 andcamera 104 have left the temporary network 200 in S1103 and S500 and,hence, no STA remains in the temporary network 200 (“NO” at 1201).Accordingly, the CPU 400 of the display 102 halts the AP function (S503)and the display 102 returns to the home network 105 (S506 to S508) in amanner similar to that of the first embodiment.

In accordance with the second embodiment, the user of camera 104, whichis the command terminal, is capable of using the display 102 within thetemporary network 200 even in a case where the printer 103, which is thecommanded terminal, has left the temporary network 200.

Further, the terminal function notifications made in S1100 and S1101 maybe performed only by the communication apparatus for which the logicalfunction is that of the command terminal. In this case, it can be soarranged that the notification is made in synch with pressing of aplayback button (not shown) on the user interface of the camera 104.

Further, in the second embodiment, whether or not the logical function1003 of the communication apparatus that has left the temporary networkis that of the command terminal is adopted as a criterion. However,whether or not the communication apparatus is the communicationapparatus that requested the construction of the temporary network 200may be adopted as the criterion. In this case, the CPU 400 of thedisplay 102 stores as the command terminal the communication apparatusthat issued the request, this being stored as logical function 1003 ofSTA management register 900 (S1102).

[Third Embodiment]

Next, a third embodiment of the present invention will be described indetail with reference to the drawings. Described in the third embodimentis a case where a plurality of communication apparatuses serving ascommand terminals described in the second embodiment exists in thetemporary network 200.

It should be noted that the communication apparatuses constituting thenetwork and the structure of the apparatus are the same as those of thesecond embodiment described above in conjunction with FIGS. 1 to 3 andFIG. 9.

FIG. 13 is a diagram illustrating an example of communicationapparatuses connected to the temporary network 200 in the thirdembodiment. The third embodiment relates to a state in which after thetemporary network 200 is constructed as in the manner of the firstembodiment, a digital still camera 1300 serving as a command terminal isconnected to the temporary network.

FIG. 14 is a diagram illustrating an example of the STA managementregister 900 of the display 102 in the third embodiment. Here Serial No.3 under serial number 1000 is information relating to the camera 1300.The logical function 1003 of the camera 1300 is that of the commandterminal.

Reference will now be had to FIGS. 15 and 16 to describe operation inwhich, after all command terminals have left the temporary network 200,a return to the home network 105 is performed based upon informationthat has been stored in the STA management register 900 of the display102. It should be noted that operations similar to those of the firstand second embodiments need not be described again; only operations thatdiffer will be described.

FIG. 15 is a sequence diagram illustrating communication control forallowing each communication apparatus to return from the temporarynetwork to the home network in the third embodiment, and FIG. 16 is aflowchart illustrating communication control of a communicationapparatus in the third embodiment. It should be noted that thiscommunication control is executed by the communication controllers ofthe camera 104, display 102, printer 103 and camera 1300.

First, after the temporary network 200 is constructed by the camera 104,display 102 and printer 103, the camera 1300 issues a connection requestto the display 102 (S1500). The display 102 then sends the camera 1300 aresponse to the connection request (S1501). When the camera 1300 joinsthe temporary network 200, the CPU 400 of the camera 1300 notifies thedisplay 102 of the terminal information (S1502). Upon receiving theterminal information notification, the CPU 400 of the display 102 storesthe received information in the STA management register 900 (S1403).

The STA management register 900 of the display 102 at this time storesinformation in the manner shown in FIG. 14. Specifically, Serial No. 3is information relating to the camera 1300, for which the MAC address1001 is “cc:cc:cc:cc:cc:cc”, the physical function 1002 is “STA” and thelogical function 1003 is “command terminal”.

Next, when the camera 104 leaves the temporary network 200 in S500, theCPU 400 of the display 102 determines whether a command terminal existsin the temporary network (1600 in FIG. 16). Since the camera 1300 ofSerial No. 3 exists as a command terminal (“YES” at 1600), the CPU 400of the display 102 returns to the decision step 602. As a result, thecamera 1300 is capable of executing an application (e.g., printing)together with the printer 103 (S1504).

Next, the camera 1300 leaves the temporary network 200 (S1505). Whenthis occurs, the CPU 400 of the display 102 determines whether a commandterminal exists in the temporary network 200 (1600). As a result, sincethe camera 1300 that was the sole command terminal existing in thetemporary network 200 has left the temporary network 200, the CPU 400 ofthe display 102 determines that no command terminal exists (“NO” at1600). From this point onward, the CPU 400 of the display 102 notifiesthe printer 103 that the temporary network has been left and the display102 and printer 103 return to the home network in a manner similar tothat of the first embodiment.

In accordance with the third embodiment, if a plurality of commandterminals exists in the temporary network 200, all communicationapparatuses can return from the temporary network to the home networkafter all of the command terminals have left the temporary network.

[Fourth Embodiment]

Next, a fourth embodiment of the present invention will be described indetail with reference to the drawings. In the first to thirdembodiments, management of information (FIGS. 10 and 14) relating tocommunication apparatuses and notification of the communicationapparatuses (S1102; 607) that the temporary network has been left arecarried out by the display 102, which is the AP of the temporary network200. However, such management and notification that the temporarynetwork has been left may just as well be performed by a STA within thetemporary network. In the fourth embodiment, a case in which the printer103 performs management and gives notification that the temporarynetwork has been left will be described.

FIG. 17 is a sequence diagram illustrating communication control forallowing each communication apparatus to return from the temporarynetwork to the home network in the fourth embodiment, and FIG. 18 is aflowchart illustrating communication control of a printer in the fourthembodiment. FIGS. 19 to 21 are diagrams illustrating the content of theSTA management register 900 of printer 103.

After the camera 1300 forms the temporary network as described in thethird embodiment, the CPU 400 of a display 102 receives notification ofterminal information from the camera 1300 in S1502. Next, the CPU 400 ofthe display 102 transfers the notification of terminal information tothe printer 103 (S1700). As a result, the CPU 400 of the printer 103stores the received terminal information in its own STA managementregister 900 (S1701; 1800). FIG. 19 is a diagram illustrating thecontent of the STA management register 900 of the printer 103. Underthese conditions, Serial Nos. 1, 2 and 3 are items of informationrelating to the camera 104, display 102 and camera 1300, respectively.

When the camera 104 subsequently leaves the temporary network 200 inS500, the display 102 detects that it has left and so notifies theprinter 103 (S1702). When the CPU 400 of printer 103 receives thisnotification from the display 102 and detects that the camera 104 hasleft the temporary network (“YES” at 602), the CPU 400 of printer 103determines whether the physical function of the communication apparatusthat has left the temporary network is that of an AP.

Here the communication apparatus that has left the temporary network isthe camera 104 (Serial No. 1) and the physical function is that of theSTA (“NO” at 1802). Accordingly, the CPU 400 of printer 103 updates itsown STA management register 900 based upon this notification (S1703;1800). The content of the STA management register 900 under theseconditions is shown in FIG. 20. As illustrated in FIG. 20, theinformation under Serial No. 1 has been erased because the camera 104left the temporary network 200 in S500.

Next, when the camera 1300 leaves the temporary network 200 in S1505,the CPU 400 of display 102 detects this and notifies the printer 103 ofdetection (S1704). Upon receiving this notification and detecting thatthe camera 1300 has left the temporary network (“YES” at 602), the CPU400 of the printer 103 determines whether the physical function of thecommunication apparatus that has left the temporary network is that ofan AP.

Here the communication apparatus that has left the temporary network isthe camera 1300 (Serial No. 3) and the physical function is that of theSTA (“NO” at 1802). Accordingly, the CPU 400 of the printer 103 updatesits own STA management register 900 based upon this notification (1800).The content of the STA management register 900 under these conditions isshown in FIG. 21. As illustrated in FIG. 21, the information underSerial No. 3 has been erased because the camera 1300 left the temporarynetwork 200 in S1505.

Next, after it updates the STA management information at 1800, the CPU400 of the printer 103 determines whether a communication apparatuswhose logical function is that of a command terminal exists in thetemporary network 200 (1801). As illustrated in FIG. 21, a communicationapparatus whose logical function is that of a command terminal no longerexists in the temporary network 200 (“YES” at 1801).

Accordingly, the CPU 400 of the printer 103 notifies the display 102 ofthe fact that the temporary network has been left (S1706; 1803) and areturn to the home network 105 is carried out (610).

It should be noted that in a case where the display 102, which is theAP, has left the temporary network 200 (“YES” at 1802), the printer 103returns to the home network 105 (610).

Further, the arrangement is such that the camera 1300 notifies thedisplay 102 of terminal information in S1502 and the display 102transfers this terminal information to the printer 103 in S1700.However, it may be so arranged that the camera 1300 notifies all of thecommunication apparatuses in the temporary network 200 of terminalinformation by broadcast in S1502.

Further, in the fourth embodiment, the printer 103 manages informationrelating to communication apparatuses and notifies of the fact that thetemporary network has been left. However, it may be so arranged thateach communication apparatus in the temporary network 200 manages thisinformation and returns to the home network 105 autonomously at themoment a command terminal no longer exists (“YES” 1801). In this case,since each communication apparatus manages the information, it isunnecessary to notify the AP (S1706) that the temporary network has beenleft.

Further, in the first to fourth embodiments, a case where communicationbetween a STA (camera 104, printer 103, camera 1300) and an AP (display102) is severed has been described. However, similar effects areobtained even if a communication apparatus leaves a logical connection.An example of a logical connection that can be mentioned is UPnP(Universal Plug and Play),

The present invention may be applied to a system constituted by aplurality of devices (e.g., host computer, interface, reader, printer,etc.) or to an apparatus comprising a single device (e.g., a copier orfacsimile machine, etc.).

Furthermore, it goes without saying that the object of the invention isattained also by supplying a recording medium storing the program codesof the software for performing the functions of the foregoingembodiments to a system or an apparatus, reading the program codes witha computer (e.g., a CPU or MPU) of the system or apparatus from therecording medium, and then executing the program codes.

In this case, the program codes per se read from the recording mediumimplement the novel functions of the embodiments and the recordingmedium storing the program codes constitutes the invention.

Examples of recording media that can be used for supplying the programcode are a flexible disk, hard disk, optical disk, magneto-optical disk,CD-ROM, CD-R, magnetic tape, non-volatile type memory card or ROM, etc.

Further, not only are the functions of the above-described embodimentsimplemented by executing program code that has been read by a computer;the following case is included as well. Specifically, an operatingsystem or the like running on the computer executes some or all of theactual processing based upon the indications in the program codes, andthe functions of the above-described embodiments are implemented by thisprocessing.

Furthermore, it goes without saying that the following case also isincluded in the present invention. Specifically, program code read froma recording medium is written to a memory provided on a functionexpansion board inserted into the computer or provided in a functionexpansion unit connected to the computer. Thereafter, a CPU or the likeprovided on the function expansion board or function expansion unitperforms some or all of actual processing based upon the indication inthe program codes, and the functions of the above embodiments areimplemented by this processing.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2008-066735, filed Mar. 14, 2008, which is hereby incorporated byreference herein in its entirety.

The invention claimed is:
 1. A communication apparatus comprising: aprocessor coupled to a memory, wherein the processor is configured toact as units comprising: (1) a creating unit which operates as an accesspoint and creates a first wireless network; (2) a communication unitwhich communicates with a first terminal apparatus and a second terminalapparatus which participate in the first wireless network, wherein thefirst terminal apparatus is a specific apparatus and the second terminalapparatus is not a specific apparatus; (3) a detecting unit whichdetects that the first terminal apparatus or the second terminalapparatus has left the first wireless network created by the creatingunit; and (4) an ending unit which (a) maintains the operation as theaccess point of the first wireless network, in a case that the secondterminal apparatus left the first wireless network and the firstterminal apparatus remains in the first wireless network, and (b) endsthe operation as the access point of the first wireless network, in acase that the first terminal apparatus left the first wireless networkeven if the second terminal apparatus remains in the first wirelessnetwork.
 2. The communication apparatus according to claim 1, whereinthe processor is further configured to act as a transmitting unit whichtransmits a predetermined signal to another terminal apparatus of thefirst wireless network, in a case that the detecting unit detects thatthe first terminal apparatus or the second terminal apparatus has leftthe first wireless network.
 3. The communication apparatus according toclaim 1, wherein the processor is further configured to act as aconnecting unit which connects to a second wireless network, in a casethat the detecting unit detects that the first terminal apparatus hasleft the first wireless network.
 4. The communication apparatusaccording to claim 3, wherein the connecting unit connects to an accesspoint of the second wireless network.
 5. The communication apparatusaccording to claim 3, wherein the connecting unit connects to the secondwireless network as a terminal apparatus of the second network.
 6. Thecommunication apparatus according to claim 1, wherein the specificapparatus is an apparatus that performs a specific function.
 7. Thecommunication apparatus according to claim 6, wherein the specificfunction is a function that issues an execution instruction of anapplication that can be executed by the communication apparatus.
 8. Thecommunication apparatus according to claim 7, wherein the application isa print application, and the execution instruction is a printinstruction.
 9. The communication apparatus according to claim 1,wherein the specific apparatus is an apparatus that requested thecommunication apparatus to create the first wireless network.
 10. Thecommunication apparatus according to claim 1, wherein the first wirelessnetwork is compliant with the IEEE 802.11 standard.
 11. A communicationcontrol method of a first communication apparatus, the communicationcontrol method comprising: operating as an access point and creating afirst wireless network; communicating with a first terminal apparatusand a second terminal apparatus which participate in the first wirelessnetwork, wherein the first terminal apparatus is a specific apparatusand the second terminal apparatus is not a specific apparatus; detectingthat the first terminal apparatus or the second terminal apparatus hasleft the first wireless network; maintaining the operation as the accesspoint of the first wireless network, in a case that the second terminalapparatus left the first wireless network and the first terminalapparatus remains in the first wireless network; and ending theoperation as the access point of the first wireless network, in a casethat the first terminal apparatus left the first wireless network evenif the second terminal apparatus remains in the first wireless network.12. A non-transitory computer-readable medium encoded with acomputer-readable control program which, when executed by a processor ofa first communication apparatus, will cause a computer to execute acommunication control method, the communication control methodcomprising: operating as an access point and creating a first wirelessnetwork; communicating with a first terminal apparatus and a secondterminal apparatus which participate in the first wireless network,wherein the first terminal apparatus is a specific apparatus and thesecond terminal apparatus is not a specific apparatus; detecting thatthe first terminal apparatus or the second terminal apparatus has leftthe first wireless network; maintaining the operation as the accesspoint of the first wireless network, in a case that the second terminalapparatus left the first wireless network and the first terminalapparatus remains in the first wireless network; and ending theoperation as the access point of the first wireless network, in a casethat the first terminal apparatus left the first wireless network evenif the second terminal apparatus remains in the first wireless network.